The present invention relates generally to regulating energy that is supplied to electronic circuits and particularly to regulating energy within integrated circuits (ICs).
Many electronic systems use supply voltage and/or supply current regulators to provide a stable supply of energy to a sensitive circuit; to provide energy at a different level than is available from the original energy source; and/or to shield an energy source from noise generated by one of the circuits that is using its energy. For instance, a 3.3V battery may be used as an energy source for a sensitive analog circuit operating at 1.5V and a noisy digital circuit operating at 1.0V. By providing the supply voltage for the analog circuit through a first regulator that bridges a 1.8V level shift and providing the supply voltage for the digital circuit through a second regulator that bridges a 2.3V level shift, the analog circuit may be protected twice from noise generated by the digital circuit that may otherwise leak via their battery connections. And both circuits can receive stable supply voltages mostly independent of the battery voltage which may gradually reduce as the battery's charge is used up. Regulators typically include an input for receiving raw energy from a power supply, a regulated output to which a power load may be connected, a reference input, and a ground terminal. A high-efficiency regulator forwards most of the energy received at the input to the power load, and loses only little energy flowing away through the ground terminal.
Regulators often use a filter that may act as an energy buffer to smooth the energy level at its regulated output. They also often use a filter for the regulation mechanism itself, which may be achieved in a negative feedback loop, wherein the regulated energy level is compared with (subtracted from) a reference level. In those cases, a well-designed filter provides stability for the feedback loop.
Power management in complex integrated circuits (ICs) may require multiple regulators, often integrated, to support multiple power domains and multiple modes of activity, such as OFF, various levels of standby and sleep mode, and a fully active mode. In some cases, circuits may abruptly switch from a power-saving mode to fully active mode, and the noise spectrum of energy used may change instantly. Conventional regulators are not adapted for such a change, and as a result, circuits may not be used in the most power saving mode available. Therefore, ICs with conventional regulators may use more energy than necessary. The present invention overcomes this problem and helps circuits operate at the lowest average power possible.
Reference to any prior art in the specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in Australia, USA, or any other jurisdiction or that this prior art could reasonably be expected to be ascertained, understood and regarded as relevant by a person skilled in the art.